Hi Catalin,
On 27/06/16 15:39, Catalin Marinas wrote:
> On Mon, Jun 27, 2016 at 12:18:42PM +0100, James Morse wrote:
>> This if() {} hunk isn't necessary with the version of
>> cpus_are_stuck_in_kernel()
>> you have in patch 2. This logic is the '|| smp_spin_tables' part of that
>> helper
>> function. (hibernate needed it too)
>
> I can make the changes locally but just to be clear I understand what
> you meant, here's the diff on top of Geoff's patch:
Ah, I see my 'if() {}' comment is ambiguous as there are two ...
>
> ----8<-------------------------
>
> diff --git a/arch/arm64/kernel/machine_kexec.c
> b/arch/arm64/kernel/machine_kexec.c
> index 945ce326654c..bc96c8a7fc79 100644
> --- a/arch/arm64/kernel/machine_kexec.c
> +++ b/arch/arm64/kernel/machine_kexec.c
> @@ -68,24 +68,9 @@ int machine_kexec_prepare(struct kimage *kimage)
>
> kexec_image_info(kimage);
>
> - if (kimage->type != KEXEC_TYPE_CRASH) {
> - if (cpus_are_stuck_in_kernel()) {
> - pr_err("Can't kexec: failed CPUs are stuck in the
> kernel.\n");
> - return -EBUSY;
> - }
> -
> - if (num_online_cpus() > 1) {
> - if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
> - /* any_cpu as we don't mind being preempted */
> - int any_cpu = raw_smp_processor_id();
> -
> - if (cpu_ops[any_cpu]->cpu_die)
> - return 0;
> - }
> -
> - pr_err("Can't kexec: no mechanism to offline secondary
> CPUs.\n");
> - return -EBUSY;
> - }
> + if (kimage->type != KEXEC_TYPE_CRASH && cpus_are_stuck_in_kernel()) {
> + pr_err("Can't kexec: CPUs are stuck in the kernel.\n");
> + return -EBUSY;
> }
>
> return 0;
> @@ -163,7 +148,7 @@ void machine_kexec(struct kimage *kimage)
> /*
> * New cpus may have become stuck_in_kernel after we loaded the image.
> */
> - BUG_ON(cpus_are_stuck_in_kernel() && (num_online_cpus() > 1));
> + BUG_ON(cpus_are_stuck_in_kernel() || (num_online_cpus() > 1));
>
> reboot_code_buffer_phys = page_to_phys(kimage->control_code_page);
> reboot_code_buffer = phys_to_virt(reboot_code_buffer_phys);
>
Yes, that's what I meant, thanks Catalin.
The 'num_online_cpus() > 1' is still needed as disable_nonboot_cpus() called via
machine_shutdown() may have failed and this is where we check. (we can't return
an error from either path).
Geoff, I assume you agree?
Thanks,
James
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